The chemistry of cyclopropanones and other reactive intermediates will be explored in order to develop novel transformations useful in organic synthesis. Among the systems to be investigated will be cyclopropanone hemiketals and animals capable of providing the parent ketones in situ for reaction with nucleophilic reagents. Studies in this series have already yielded a new general synthesis of the Beta- lactam grouping. This ring enlargement reaction is being extended to the preparation of Beta-lactam derivatives of a variety of amino acids, some of them related to penicillin.